Safety
The teaching and practice of organic chemistry has undergone major changes in the past few
years with regards to the safe handling and disposal of chemicals and this is likely to continue. Some
chemicals such as benzene, commonly used as a solvent a few years ago, have practically disappeared
from the laboratory. The use of other chemicals such as carbon tetrachloride are slowly being phased
out. Nevertheless the use of many substances of variable toxicity will continue both in industry and
academia and it is the obligation and responsibility of a laboratory course in organic chemistry to
instruct the student in the safe use and disposal of these substances.
The following safety rules constitute a beginning in establishing a safe laboratory environment:
a. Eye protection must be worn at all times the laboratory is in session. This is a regulation of
the State of Missouri. The wearing of approved eye protection can be met by several different types of
glasses or goggles. If you normally wear glasses, these may be suitable provided the lenses are made of
safety glass. Most plastic lenses meet or exceed the specifications of safety glass and are acceptable.
Students wearing plastic lenses should be aware that the lenses can be attacked by some of the solvents
used in the laboratory and some loss of the optical properties can occur if the two come in contact. It is
also recommended that a pair of inexpensive safety side shields be purchased from the bookstore. These
shields attach on the side of your glasses and offer protection against peripheral splashes.
Students that do not normally wear glasses are encouraged to purchase a pair of goggles or noncorrecting glasses. Although goggles offer the best eye protection, they also have a tendency to fog up
thereby reducing vision. Goggles are not intended to protect the forehead! Be sure to purchase a pair
that affords plenty of ventilation.
The wearing of contact lenses in the laboratory is strongly discouraged. Material that comes in
contact with the eye as a result of a splash is considerably more difficult to remove if the person is
wearing contact lenses. Photo chromic glasses are acceptable but sunglasses are not unless there are
extenuating medical circumstances which require such glasses.
Everyone should be aware of the location of the nearest eyewash; getting to an eyewash quickly
can help to save your sight.
b. Clothing that is worn offers important protection. In a chemical spill, if the chemical is a liquid,
it will be absorbed by the clothing and while the clothing should be removed as quickly as possible,
contact with the skin is kept to a minimum. The wearing of old jeans is recommended, but clothing
covering as much exposed surface as reasonable should be worn. The wearing of shorts or sandals is
discouraged unless covered by an appropriate laboratory coat or apron. No shoes, no shirt, no
laboratory.
In addition to dressing properly for the laboratory, be sure to take advantage of the protection
that the pair of "disposable" rubber gloves (included in your kit) can provide when you are handling
strong acids and bases or other toxic materials. These gloves can be reused indefinitely, provided they
are not torn, by simply washing them with soap and water. A small amount of talc or other similar
powder will assist inserting your hands in the gloves.
c. No food or beverages are allowed in the laboratory. Be sure to wash your hands when you leave
the laboratory, particularly if you are going out for snack. Remember that even after washing your
hands with soap and water, some "memory" of the materials you have been working with is retained on
your hands.
d. Open flames are not allowed in the laboratory. Fires have been one of the major causes of
accidents in the laboratory. For those experiments that require an open flame (the preparation of glass
capillaries used in thin layer chromatography), a special hood in the laboratory will be designated for
use. Hot plates, electric heating mantles and steam baths will be used as sources of heat instead. While
the use of other sources of heat has eliminated the cause of most fires, the risk of fire has not been
totally eliminated. Many of the organic solvents in use today are quite volatile, quite flammable and
can be ignited given the right conditions. Heating solvents should always be conducted in a well
ventilated area such as a hood. You should also be aware of the properties of the common solvents you
are using, particularly their flash points. Although not used as a common solvent, carbon disulfide will
spontaneously ignite on a steam bath if the vapors are heated above about 80 C. While the risk of
fires has been reduced, significantly, you should be aware of the location of the nearest fire
extinguisher. Most laboratories are also equipped with a fire blanket and safety shower. When you are
in the laboratory, take a minute to read how to operate the device. This could come in handy later on.
e.
If, during the course of a laboratory, you are injured, no matter how minor, you should bring this
to the attention of the instructor or teaching assistant. If the injury does require some medical attention,
the instructor or teaching assistant will escort you to the Campus Health Center. In case of a serious
injury, you will be escorted to the appropriate medical facility. Students should be aware that in the
event that either the teaching assistant and/or instructor must leave the laboratory, and the other is
unavailable, you will be asked to stop work until they return.
In the case where you spill a chemical on your skin and there is other immediate damage,
remove as much of the chemical from your skin by using a towel and then wash very well with soap and
water. The laboratory is equipped with a safety shower located by one of the doors. This shower is
designed to deliver a large volume of water in a short period of time and should be used in case of a
fire or large chemical spill on an individual.
While it would take a long discussion to describe the different types of accidents that can
happen in an organic laboratory, it may to useful to describe the most common accident in the
laboratory that usually requires some sort of medical attention. The most frequent type of accident is
usually associated with inserting or removing a thermometer or glass tubing in or from a rubber stopper.
While the need for rubber stoppers and glass tubing has been greatly reduced with the use of ground
glass joints and other changes, please heed the following advice if you need to insert or remove a glass
rod into a rubber stopper. Always use a lubricant such as stopcock grease to lubricate the shaft. Do not
force or apply excess pressure to dislodge or insert a stopper and use a towel as an intermediary
between you and the glass. Instead of pushing the glass rod or thermometer in or out, try using a
pulling, twisting motion instead. Don't hesitate to ask for assistance. In trying to insert or remove your
Teflon thermometer adapter from your thermometer, use the steam in the hood to heat and lubricate.
Once heated, the Teflon will expand and slide much easier down the shaft of the thermometer.
f.
Chemicals are generally not to be disposed of by flushing down the sink or simply tossing in
the trash. While many of the materials you will be working with in this course can be safely disposed
of in this way, get into the habit of following the suggested disposal directions and of asking your
instructor how to properly dispose of your wastes. Solid wastes will either be collected in an appropriate
container or you will be instructed to use the trash containers. Please note that the laboratory is
equipped with special waste containers for glass. Liquids are generally segregated into either
halogenated or non-halogenated wastes and containers for these materials are kept in a corner in the
laboratory. Acetone is usually used to wash and dry glassware in the laboratory. While it is acceptable
to flush wash acetone down the drain, provided plenty of water is used to dilute it and reduce the
possibility of fire, collect your wash acetone in a beaker and dispose of it in the container specifically
designated for wash acetone.
g.
Take only as much of the reagents as you need. In the event you have any excess reagent left
over, ask your instructor how to dispose of it properly. Accidental contamination of reagents is not only
unfair to your colleagues, it can be down-right dangerous. Potassium permanganate in contact with
glycerol and other organics can spontaneously ignite.
h.
Ingestion of chemicals can occur in several obvious and some less obvious mechanisms. The
tasting of laboratory chemicals, once a common practice, is no longer an acceptable practice. Many
organic solvents are quite volatile and a common exposure to these substances is through the lungs. The
vapors of some common solvents such as the simple halogenated methanes, can cause liver damage and
some are suspected of being carcinogenic. Avoid breathing the vapors of these materials and always
work with these materials in a well ventilated area such as a hood. Many organic solvents are also
rapidly absorbed through the skin. It is a good idea to use the disposable gloves when handling these
materials. Organic ethers pose fire hazards. The vapors of diethyl ether can accumulate in troughs or
on the floor and can be ignited by remote sparks or flames. Additionally, the more highly substituted
ethers react readily with oxygen to form potentially explosive peroxides. Avoid distilling ethers to
dryness.
i.
Proper laboratory practices, neatness and organization in the laboratory are considered closely
associated with safety. A neat and well organized student is usually less likely to have an accident and
more likely to get a better grade. Come to laboratory prepared. Be sure to read the experiment before
coming to lab and run through how you will complete the experiment in your mind before you try it
with your hands. Look up the properties of the materials you will be working with and be aware of any
precautions associated with any of these substances. Ask questions if any part of the experiment is
unclear to you.